PhD Student University of Georgia Athens, Georgia, United States
The American cockroach (Periplaneta americana) is an omnivorous insect found across the world, often in association with humans, that thrives in the most unlikely of conditions. P. americana is especially adept at surviving on extremely diverse diets, in part due to its symbiotic gut microbial community that is known to provide the host with vitamins and fatty acids. However, studies exploring the relationship between host diet and microbiome in the cockroach have been inconclusive. Through the use of nutritionally-complete synthetic diets, my research distinguishes how precise substrate alterations, particularly carbohydrate source, alter the microbiome in the foregut, midgut, and hindgut of P. Americana. Differences arose in 16S rRNA-identified taxa across gut region and dietary treatment, such as a chitin-driven increase in spirochaetes in the midgut, and increases in termite-related taxa in cockroaches fed cellulose-based diets. The addition of xylan to the diets generated large shifts across all regions as visualized in NMDS plots, leading to further analysis of how increasing ratios of xylan to cellulose modified different taxa populations in a dose-dependent manner. Ongoing studies are being performed to associate diet-driven community alterations with both host and microbiome transcriptional activity, in addition to using RNA interference to modify host nutritional provisioning to the gut. These findings highlight the importance of investigating precise alterations in diet composition when relating host diet to the microbial community, to properly dissect host-symbiont interactions without confounding host fitness levels.
